Not just Azure
Years ago, I had to become MS certified. Had a choice of anything SQL or Windows Server related. I took the Windows 2000 course. The exam was trivial, but the content covered was an excellent foundation course on general OS stuff - networks, RAID etc. It's all come in really useful over the years.
Last year, I looked at finally updating to Windows Server 2016. Massive text book containing nothing more than vast quantities of Powershell commands to be memorised. Unless you're doing nothing but windows admin all day every day, you don't use this stuff often enough for it to be useful.